Strain glass versus antisite disorder induced ferromagnetic state in Fe doped Ni-Mn-In Heusler martensites

Abstract

Fe doping in Ni sub(2)Mn sub(1.5)In sub(0.5) results in suppression of the martensitic phase via two contrasting routes. In Ni sub(2)Mn sub(1.5 - x)Fe sub(x)In sub(0.5), the martensitic phase is converted to a strain glassy phase, while in Ni sub(2 - y)Fe sub(y)Mn sub(1.5)In sub(0.5), a cubic ferromagnetic phase results at the expense of the martensite. Careful studies of magnetic and structural properties reveal the presence of the impurity Gamma - (Fe,Ni) phase as the reason for the emergence of non-ergodic strain glassy phase when Fe is sought to be doped at Y/Z (Mn) sites of X sub(2)YZ Heusler alloy. Whereas attempts to dope Fe in the X (Ni) sublattice result in an A2 type antisite disorder that promotes a ferromagnetic ground state.